Okay. I'm sure we've all seen a well-done review.

It should fairly point out all of the good and bad points of the piece.
There should be NO flaming at all. We can all agree that no matter what, a review will vary depending on the person writing- this is a good thing. As such, they will naturally focus on different parts of any given anything.
Just make sure you don't overdo it, huh?

Do's:
Outlines the basis of the story without giving away too much of the plot.
Critiques if it is still in editing/writing.
Gives both pros and cons without over-amplifying any given point.
weighs those points against each other.
Uses an out of ten base score for quick viewing.
Has the date and how far along the story is at the top, along with first impression.

(title of review thread should be the name of the story and the subtitle should be the out of ten rating you give it)

Dont's
Do not EVER flame. Being constructive is one thing, being rude is another.
Focus too strongly on any one point, good or bad, unless you feel it REALLY needs the attention (make sure there's a DANGED good reason for it, too)
(i'm sure there's something else =/)